Reduced Order Estimation of the Speckle Electric Field History for Space-based Coronagraphs

In high-contrast space-based coronagraphs, one of the main limiting factors for imaging the dimmest exoplanets is the time-varying nature of the residual starlight (speckles). Modern methods try to differentiate between the intensities of starlight and other sources, but none incorporate models of space-based systems that can take into account actuations of the deformable mirrors (DMs). Instead, we propose formulating the estimation problem in terms of the electric field while allowing for dithering of the DMs. Our reduced-order approach is similar to intensity-based PCA (e.g., KLIP) although, under certain assumptions, it requires a considerably lower number of modes of the electric field. We illustrate this by a FALCO simulation of the Wide-field Infra-red Survey Telescope hybrid Lyot coronagraph (the data and the comparison code are available at https://github.com/leonidprinceton/EFOR).